: LPG, CNG or other alternative fuel conversion?



N0DIH
04-16-07, 08:28 AM
Has anyone ever converted their Cadillac over to an alternate fuel like CNG or LPG? I thought there was someone here who has.

I am curious on the conversion and how much it costs to operate the car that way. In India this is very common, as they feel it is cheaper to fuel the cars off this with less emissions than gasoline.

Higher octane, slightly less BTU's, instant able to go to closed loop operation due to gas at room temp, etc.

How much is it to fill up with CNG or LPG? How much mpg?

The Ape Man
04-16-07, 01:57 PM
A quick Google finds plenty.

http://texastransit.org/wordpress/wp-content/uploads/2006/11/PropaneSurveyResults.pdf

N0DIH
04-16-07, 02:16 PM
I was digging around, but haven't found a whole lot that I am looking for (details on the mod itself) and what is needed to do it on a EFI car, if it can be done.

Old Fleetwood
04-17-07, 02:48 PM
Years ago it was relatively simple to convert carbureted vehicles to LPG.
I saw plenty of them when I was living in the midwest.
How this would work with F.I. vehicles, I have no idea, but I don't think it would be any big deal.
BTW, it was/is unlawful for propane delivery trucks to take their engine fuel from the big, main delivery tank.
Their fuel had to come from a separate tank.
The wonderful thing about LPG is that it burns VERY clean.
The vehicles I saw at tear-down for overhaul at 1/2 million miles ( ! ) looked like they had totally clean cylinder heads and valves.
The wear occured on the crank, cam and rods.

N0DIH
04-18-07, 04:57 PM
Just wondering the cost effectiveness of the LPG, CNG or Propane in a modern 10:1 compression LT1 compared to E85 or gas.

z06bigbird
04-18-07, 05:44 PM
I converted an old Ford truck to propane. 115 gallon tank in back. In a car, you would have two interconnected tanks, each about 30 inches long and about 6 inches in diameter.

They take up a good part of your trunk space.

On a veh with a carb, you just bolt a part on top of the carb. It also has a butterfly valve that allows you to switch between gasoline and propane. A solenoid will shut off the gasoline; another turns on the propane.

Then you run your heater hoses into to pressure regulator to warm up the propane. Without warm water, the pressure regulator will turn into a temporary block of ice.

Between the propane and the gasoline, I had about a 2000 mile range. At that time, propane for auto purposes sold for 60 cents per gal. Gasoline was $1.00. Ask the right questions when you call about automotive propane because propane used on the farm is not charged some of the taxes.

Propane burns clean, no varnish. You lose about 10% efficiency. No spark knock, no drop in performance.

I did not drive veh much, and I used to fill it up 3 or 4 times per year.

I loved it. No complaints.

After you install the kit, you need a special inspection sticker because veh that run on propane can blow up. Inspection is designed to eliminate those 'little problems.'

Ed

N0DIH
04-18-07, 11:46 PM
Gotta admit, it would be nice to be able to run for 2000 miles!!

I would like to look into it some, but with EFI and the PCM, making it think all is fine would be interesting. I have a large trunk, so I was wondering what sort of tanks I could put in it after I remove the spare tire and mount it there. I would need dual fuel. But I would need a place I could come and fill the car up with it.

z06bigbird
04-18-07, 11:54 PM
Gotta admit, it would be nice to be able to run for 2000 miles!!

I would like to look into it some, but with EFI and the PCM, making it think all is fine would be interesting. I have a large trunk, so I was wondering what sort of tanks I could put in it after I remove the spare tire and mount it there. I would need dual fuel. But I would need a place I could come and fill the car up with it.

Tanks are bulky, and they (it) will take up half of trunk space.

Ed

Old Fleetwood
04-18-07, 11:54 PM
Toss the spare and go to Run-Flat tires.
I haven't measured the space under the rear window in the trunk, but it looks like it could hold a substantial cylinder with the spare removed.
That might make for a VERY interesting vehicle.
But what's the cost of propane these days compared to gasoline?
Then, as noted above, with a 10% loss (similar to alcohol?) what REAL comparisons can be made?
(Here come de spreadsheet)

N0DIH
04-18-07, 11:55 PM
Triple Fuel? E85, Gas and Propane?

Old Fleetwood
04-18-07, 11:57 PM
But wouldn't that get into REALLY re-programming the chip?:confused:

N0DIH
04-19-07, 12:30 AM
Yup!!! and I would have a ball doing it!!

deVille33
04-19-07, 11:07 PM
There is a guy up in Canada who has a 70's Cadillac (425 cu. in. ) that he runs on LP. It's hard to understand what he's trying to say, his English skills are not great.
He has a problem with the valves maintaining the vaporized fuel. The fuel finds its way past the valve seals. Because the LP burns cooler the valve stems are cooler and may not maintain proper clearance.
He was having a pair of heads done over and another set of valve seals installed as an experiment. I haven't gone back there to see how he made out.

Old Fleetwood
04-19-07, 11:48 PM
deVille33 - It would be interesting to keep in touch with that guy. If he's on the web, you might be able to get an "automatic" translation if his language skills aren't the best.
N0DIH - The triple fuel programming stuff looks - to me - like a real nightmare. You're welcome to it. I envision almost infinite parameters of fuel, engine speed, air velocity (before and after various sensor positions), fuel temp, fuel type, vehicle load, engine temp, ambient temp, and on and on, ad infinitum, let alone emission concerns.
I'm too old for that stuff. I guess it's just right for you young guys.